Bars Stop Leak Water Pump
Saints defense mechanism
defense mechanism of the SS
Breaker:
I. Introduction
The main functions of a circuit breaker interrupts the short circuit current, driven by currents normal OFF normal docking and charging, and providing the necessary isolation between the live parts and ground parts. Problems related to maintenance the bulk oil circuit switches were immense. Minimum oil technology had replaced the bulk petroleum technology in 1950. Similarly, air-jet technology has been developed to obtain higher performance characteristics. However, switches air jet are quite expensive and their operation and maintenance difficulty. Since both, and felt the need for reduced maintenance in 1960.
SF6 was first obtained fluoride and sulfur in 1900 by M / s. H. MOSS and PLEBEAU. Behavior of SF6 in the electric field has been studied by m / s HG Cooper and PS in 4936 PQLLOCK known for over two decades, perfection is reached at the farm in 1960. These developments have enabled low-pressure SF6 gas be used in isolation switches and BIN are "for cooling purposes, part of SF6 excellent properties that make it ideal in the MAT circuit. switches are:
1. Inertia
2. No toxicity
3. Electro negative nature
4. High dielectric
Five. Cooling are the exclusive property
6. Chemical and thermal stability
7. Good thermal conductivity
8. Noncorrosive
9. No Flammable
The combined electrical, chemical, physical, thermal and SF6 provides the following features outstanding when used in the power switch circuit.
1. Security
2. Shrink
3. Weight reduction
4. Design simplified
Five. high reliability
6. Capacitive current switching without restarting
7. Very trailer noise
8. Manageable
9. Easy Installation
10. Without maintenance services
2. Properties of sulfur hexafluoride (SF6)
a) Physical characteristics:
SF6 is a colorless, odorless, nonflammable. The fluorine atoms are placed in the corners of a regular octa hedra with the sulfur atom placed in a central position at a distance of 1.58 Angstrom units. The bonds are predominantly covalent and the equation of dissociation
SF6 – to SF5 + F __________
The decomposition potential is 15.7 eV. SF6 gas is very heavy and its density is about 5.5 times that of air. It is very stable. Indeed compressible than air and follows the ideal gas law.
b) Electrical properties:
Di-electric strength SF6 is 3 times that of air at atmospheric pressure and is only slightly reduced by the presence of air as an impurity. The increase in dielectric strength with increasing pressure. At a pressure of three bars, the dielectric is equal to the transformer oil. The size of the molecule and electro negativity explain this resistance. The molecule provides a diameter electronics collision. This results in the capture of electrons will be unable to supply sufficient power to create others. Charged particles present. also capable of storing energy on the electronic and vibration levels "of the molecule SF6moiecuie not by the formation of ions stable low mobility.
Dielectric strength of SF6 is unchanged with the passage of a wide range of frequencies. SF6 has been no dipole moment, dielectric constant does not vary with frequency. AT 27.30cy atmospheric pressure is the dielectric constant and the angle of 1.00191 loss is 2 x 10-7.
The dielectric properties of SF6 will not change, even at low temperatures. Unlike insulation solid electrical defect in the SF 6 does not lead to permanent damage to their properties. You lose control over all computers office can lead to a significant increase in pressure due to gas formation, but these risks do not exist in the case of SF6-filled equipment.
c) Arc cooling properties:
The cooling capacity is one arc of SF 6. Result is the high dielectric strength and gas recovery very fast dielectric strength occurs after bow. SF6 is about 100 times more efficient in this regard that the air under similar conditions. The low arc time constant and its ability to absorb free electrons due electro negative nature, it is a great way to interrupt the arc. The movement of SF6 molecular complex allows it to absorb energy electric form stable negative ions. His tendency to the formation of negative ions around current zero results of the rapid disappearance of electrons released during the formation of arches. Unlike oil, forming an arc in SF6 produces no carbon deposits or carbon tracking.
electro-negative properties of SF6 may be due to several factors, including major collision diameter. If electrons lost electric field can be absorbed Before reaching enough additional energy to create particles carry current when the collision, the distribution may be slowed or even stopped. The collision diameter of the molecule of great help in SF6 capture these electrons. energy can be stored in vibrational levels of the atom SF6, forming stable negative ions of low mobility. Thus, the gas is electronegative in the nature and entertainment. capacity Large electron binding. sample so splendid performance of SF6 gas extinguishing the arc.
The arc time constant is directly proportional to the radius of the arc, it is possible to have a large number of breaks at full capacity of the switch. The characteristic the arc is such that the termination of the authority under b. In a typical case where power was the extinction of about 20 kW SF6 switch, the value of air power switch was in the hundreds of kilowatts.
Some processes of formation of ions are SF6 follows:
Resonance capture: SF6 + e-to (SF6) – SF5-+ F
the formation of positive ions: SF6 + eA (SF6) + 2e-SF5-+ H + 2e-
Excitation and dissociation: SF6 + eA (SF6) + e-+ H + e-SF5
the formation of positive and negative ions: SF + eA (SF6) eF + SF5 + – + e
d) heat transfer:
SF6 has excellent characteristics of heat transfer, an important criterion for dielectric gas in power applications. The higher molecular weight, low viscosity of SF6 allows the transfer of heat by convention, more effective than common gases. The heat transfer coefficient of SF6 is about 2.5 Tip1 air in the same conditions. Thus, when the switch is activated, the temperature rise small.
e) Wide temperature range:
SF6 gas form follows the ideal gas laws very closely. Consequently, the change pressure is small for a big change in temperature. The weaknesses of sublimation SF6 provides greater dielectric strength, even low temperature liquefaction temperature is-270C at a pressure of 12 kg / cm ². Therefore, no heating is necessary.
f) danger of:
SF6 gas is nontoxic and produces no toxic effects on the human body. But the products of decomposition produced by the discharge (SF4, SF2, S2, F2, etc.) are harmful. These products are minimized through the control switch and moisture absorption degradation products of synthetic zeolite.
g) the chemical and thermal stability:
SF6 gas is inert and is one of the substances known as reactive minimum conditions of normal operation. Can be heated in the quartz 5000C, at least not in decomposition. SF6 does not react with water, acids and alkalis. Tests have shown the almost total absence of corrosion of various metals exposed to SF6
Several constants) h:
Some of the outstanding properties of SF6 which makes it ideal for high voltage applications are:
Molecular Weight .. 146.05
Sublimation point at 1 atm .. 63.9 ° C
the gas density to 21.19 C at 1 atm .. 6.139
viscosity of liquid C 13.52 .. 0.305
Gas 31.16 C .. 0.0157
critical temperature, etc. .. 318.80
critical pressure bars .. 37.772
cu.metre critical volume / g .. 1.356
Dielectric rei N2 at least 50 Hs = 2.3 -2.5 -1.2 .. MHS
dielectric constant 25 ° C 1atm .. 1.002049 "
Conductivity Heat to 30 ° C, Cal / Sec C .. 3.36 x 10-5
3. Failure phenomena in SF6:
distribution gas occurs when the free electrons gain sufficient kinetic energy under the influence of an electric field and collide with neutral gas molecules release their electrons in external tanks. A chain reaction that results in an avalanche of electrons. In the case of greenhouse gases such as SF6 electro-negative mechanism has been slightly modified. The free electrons are associated molecules forming negative ions. SF6 SF6 Z + EA. Negative ions are too massive to produce ionization by collision. This attachment is an effective for the elimination of electrons that would otherwise have contributed to an avalanche of electrons. This particular behavior leads to dielectric high for electronegative gases.
The breakdown voltage electro-negative gas in a uniform field is a simple function of the product pressure and spacing. distribution of characteristics in non-uniform will be different because the main objective of ionization can locally by the presence of high stress regions. This is the crown. This may be due to surface roughness, sharp corners, driving floating or semiconductor particles. In teams of SF6 special care is taken to ensure that items do not exist in the transition to a distribution reasonably uniform field can be achieved.
4. Discontinuation SF6 principles:
Techniques used to break SF6 can be classified into two:
a) the dual-pressure system.
b) The system single pressure.
These can be classified as nozzle flow and a fixed dual-piston single series flow switch.
a) the dual-pressure system:
The decoupling of functions are performed in separate rooms. SF6 at a pressure of 14 kg / m². cm. is stored in a pressure chamber. It is used to cool the low pressure SF6 are (2.5 to 3.5 kg / m². Inches.) Insulation. When the contacts separate under the lack of gas at high pressure is forced into the arc region, then go to the area of low pressure. The gas exhausted in the region of low pressure is compressed and returned to the reservoir at high pressure. Arc occurs between the tip of the bow and relieve arch ring tension arc. A filter with true student remaining in the compressor inlet for all products of decomposition of gas can be absorbed before the recirculation system. A thermostat controlled heating system is provided on the high pressure tank to prevent condensation gas at low temperature.
b) the system of individual pressure:
In this case, low SF6 pressure (3 to 6.5 kg / cm square) which provides insulation and energy for the interruption. The board consists of fixed and movable contacts move, and provision of the piston in the type of balloon fixed contact. As the separation Contact moved by guilt, the piston moves forward at high speed. This compresses SF 6 in the fixed contact and to sanctify the forces of gas in the arc resulting in the temple. The force with which the explosion of gas depends on the arrangement the design of the piston and the control mechanism of energy.
Another improvement is the type where magnetic ball switches operates more strongly in the contact bar in motion by the force of magnetic repulsion. The short circuit current is passed through a set of fixed coils with the support of the Fed moving contact. A ring is placed and the secondary circuit magnetically coupled to the primary coil. This also acts as a piston ring. This interaction between the two. two fields produces a repulsive force and pushes the contact bar forward. The addition of this simple mechanism of magnetic coupling improves the disturbance of the switch.
The single pressure system has an inherent advantage of simplicity in construction. You no need for compression is needed in the double pressure. The manufacturing cost of ball type of equipment is lower.
5. Construction:
The arc suppression system uses a single pressure to dual stream synchronized design, the ball type. This leads to a simple construction.
The SF6 circuit breaker includes mainly the following:
1. Breaker Poles there.
2. tube box basis and mechanism
3. Control Unit
4. Compressor electro-hydraulic operating mechanism
1.Movable cylinder (cylinder Puffer) 2.Moving Contact
3.Fixed 4.Insulating Hawk Contct
Trapped in the piston 6.Gas 5.Fixed before compression
7.Compressed between 1 and 5 gas
8.The arc is extinguished by the ball action
5.1.Breaker Polo
The main functions of a circuit breaker pole made the change. The pole of the switch unit is composed the switch and the support insulator.
The unit consists of a tube fixed switching contact, guide tube, move the contact tip, a balloon or an explosion of the cylinder and the piston. The tube is connected to fixed contact to the upper boundary through. Contact support.
The guide tube is attached to the lower limit. The other end of the tube fixed contact and the guide tube in which they are subjected an electric arc during the interruption of the arc nozzles are provided with arc quenching. The nozzles are made of a graphite material that keeps the wear minimum contact. The tube is composed of movable contact finger contact spring disposed in the load form a ring. The front end of the tube is movable contact with a ring arc resistance insulating ring arcs high arc resistance
The explosion cylinder, which is composed of Arc resistance and high insulation material of the pipe moving contact being rigidly connected together and linked to the control rod in the insulation support. The piston explosion, which is composed of aluminum attached to the platform below the lower limit. Tube fixed contact, guide tube, move the contact tube, the cylinder and the piston explosion explosion are "all housed in a porcelain insulator. When the switch is closed current flows from the upper bound through the terminal support contact, contact tip fixed, mobile or the contact tube and the guide tube.
The insulation also support for supporting the switching unit to provide insulation between live parts and ground parts. It houses control rod (isolation), one end is connected to switch unit and the other end connected to the mechanism.
5.2. Base mechanism tube box:
The tube support base bipolar switching mechanism and the box uses tank Local air. The mechanism of the closed box of the solenoid valve, closing coil, trip coil and operation of the cylinder. tiny lever mechanism locks the whole system to transmit the force of the operation of the device box to the pole of the switch.
5.3.Control Unit:
This accommodates the gas pressure switches, gas detector density, gauge gas pressure gauge air pressure, hot-air valve, auxiliary relays, terminal blocks, power control, etc. and switch pneumatic control. The controls of the air and common systems of SF6 gas for 3-pole switch.
5.4. Compress
Because the requirement of operation is higher as is the air compressor or mechanism MOCBS operation is used electro-hydraulic.
6. The principle of arc extinction:
When the switch is closed to traffic from the bridge assembly contact with the tube fixed contact and the tube. When an opening operation is started, the explosion of the cylinder piston moves towards the fixed breath SF6 gas explosion in the cylinder is compressed to a pressure necessary to extinguish arc. The compressed gas during the previous process is released when the contacts are separated with the global movement of contacts that act as guillotine. In the moment of contact separation, the arc strikes between the front end of the nozzle mitigate arc tube and the stationary contact ring contact of the arc tube in motion. The blast of compressed gas cylinders out of free radicals that contacts separate. As the procedure Assembly of the movable contact, the arc between the front edge of the tip and the contact ring fixed arcing movable contact is moved from the ring centerpiece of the moving contacts of the guide tube nozzle, using a jet of gas and their own forces of electrodynamics. the arc is elongated by the flow axial gas injector and the lapse of security. Although the arc is interrupted, the ignition cylinder, making it resistant material arc closed all Insulation Cooling of the arch, there to protect the insulation porcelain rainbow effects. After arc extinction, the Assembly movable contact and the expansion wave is free of any part of the camera may have a transition effect or influence supplier of electric field.
7. Principle:
7.1. Opening Action:
When the trip coil is activated, the space of the pilot valve is filled with compressed air valve and fill the right moves. The space in the cylinder operating is filled with compressed air from the air and scored piston is driven rapidly to the left. rod to the piston is pulled Operating in the opening direction of the unit ball cylinder at high speed through the support insulator insulated operating rod. SF6 in the cylinder and the balloon is compressed SF6 gas explosion dies arc is generated between the movable and fixed contacts.
At the same time as the opening movement, the cam rotates and causes the solenoid to return to its original position. Accordingly, the compressed air in the space of the pilot valve is vented to the atmosphere and the valve piston load is delivered to the original. While the state is held open by the link mechanism attached to the end of the piston.
7.2. Closure:
When the closing coil is activated, the nature of the arc is rotated by the hook of being disconnected. Thus, the sector line to release the roller rotates and the piston is driven in the closing speech by the spring force of closure at the end of the closure, the link mechanism is maintained in a state that is ready for operation posterior opening.
8. Warning:
When you use the switch notes:
I) Keep the correct pressure of SF6 gas and air pressure as indicated.
2) Run the valves correctly.
3) Do not allow the entry of moisture and dust in the process of SF6 gas supply.
4) Do not pump gas pipelines and air hoses with any object.
5) Do not damage the seal and ring seal in the gas leak and air.
6) When you open the breaker by the handwheel. "
a) confirms that the circuit is not active.
b) Make sure disable the power control.
c) Check that compressed air is released into the receivers.
d) Consult the manual and the operating rod are removed before changing the receiver to process the compressed air.
7) Do not use another party to the instruction manual before filling with SF6 gas lead to the rated pressure. Do not fill the air before filling with SF6 gas.
When control of the internal parts of the switch, air flows through the system long enough and to confirm that the supply sufficient air is available before starting work.
9.Gas leak:
If a gas leak from by a point, which may result in reduced pressure and the loss of insulation properties of gas leak detection is done with the help of a halogen flame detector type. The sensor operates on the principle of SF6 absorbs a number of electrons passing through an environmental flow of electrons Free. The free electrons are generated in the area with a small radio active source in the presence of a carrier gas. These electrons are collected to the anode of the detector and give a small reference current that is amplified. When the detection probe is held near the joints of SF6-filled equipment and SF6 leaks will be variations in the power amplifier due to the absorption of electrons by SF6 valve. The variation can be directly calibrated to the magnitude of the leak.
09.02. Put an end to the presence of conductive particles:
This is done by performing a dielectric test where the test voltage is applied, there will be a national crown in the case of particles Metal or sharp edges are present. The presence within the discharge using a bat detector which is sensitive in the detection of noise due to the inner ring. The field of ultrasonic vibration is translated into audible frequencies and directly indicates the intensity sound in decibels. The probe is pressed firmly against the tube box to land while the driver is alternating current that varies the voltage. If the noise disappears low voltage, there is an intermediate voltage and the intensity increases, the fact is that the noise is due to the inner ring. It has also been observed that in some cases branched fort at the bathroom in the areas of stress and exhaustion dielectric particles leads to areas of low constraint. The effect of the implementation of the particles in the breakdown strength of SF6 is aggravated by the power frequency test voltage for the pulse voltage.
10. The performance of SF6 circuit breaker:
SF6 gas circuit breaker combines advantageous features minimum oil circuit breakers and air and has a number of additional advantages over both.
1) You can have a large number of operations at full capacity to break break without excessive wear.
2) Due to the rapid recovery dielectric strength by opening contacts during the interruption.
a) These switches are open during the change Restrict capacitive current.
b) These switches are an incentive to faults quickly and are capable of breaking all RRRV and high values
c) These switches are suitable for the closure of several short again with any reduction in switching
3) No need to change all the parts the device continuously, even after a period of ten years of service in the real system. This means there is virtually no maintenance burden for SF6 circuit breakers.
4) The operation is silent, because the gas is used in a closed circuit. There will not dump products in the arc atmosphere.
5) ball-type switches are autonomous and independent, no equipment auxiliary is required.
6) Fire Hazards deleted.
RELAY
A relay is an electrical switch that opens and closes under the control of another electrical circuit. In the original form the switch is actuated by an electromagnet to open or close one or more sets of contacts.
Operation
When a current flows through the coil, the resulting magnetic field attracts an armature that is mechanically linked to a movable contact. The movement is wealth connection with a fixed contact. When the coil current is turned off, the armature is returned by a force about half as strong as the magnetic force his relaxed position. Usually there is a spring, but gravity is also commonly used in industrial motor starters. Most relays are manufactured to operate quickly. In an application to low voltage, is to reduce the noise. In a high voltage or high current application, is to reduce the arc.
If the coil is supplied with DC, a diode is frequently installed in the coil, to dissipate energy the magnetic field in the collapse of the deactivation, which would have generated a voltage spike and cause damage to circuit components. Some relays Automotive already understand that the diode inside the relay box. In addition, a contact protection network, which consists of a capacitor and a resistor in series, can absorb the increase. If the coil is designed to be powered with air conditioning, a small brass ring curvature, you can at the end of the valve. This "circle of shadow" creates a small current phase, which increases the minimum tensile armor during the AC cycle.
By analogy with the original electromagnetic device has a solid state relay is made with a thyristor or solid state switching device. To achieve electrical isolation may be used an optical coupler is a light – emitting diode (LED), with a photo transistor.
Relay Type
- Interlocking relay
- Reed Relay
- The mercury in contact with the Relay
- polarized relay
- Relay Machine Tool
- Contactor
- contactor relays Solid
- Buchholz relay
- guided contacts relay
- SSR
- Relay protection against overloads
- And break Polo
The types of links are often:
SPST – Launch of a single pole. These two terminals that can connect or disconnect. Two for the coil, like a relay has four terminals in total. It is doubtful that the pole is normally open or normally closed. The terminology "SPNO" and "CNPC" is sometimes used to resolve ambiguity.
SPDT – Single Pole Double Throw. A common terminal connects to one of two. Two for the coil, like a relay has five terminals in total.
DPST – Double Pole once. They have two pairs of terminals. Equivalent two SPST switches or relays actuated by a single coil. Two for the coil, as a relay six terminals in total. It is doubtful that the pole is normally open, normally closed, or one of each.
DPDT - Double Pole Tyre. These two rows of pins to change the format. Equivalent two SPDT switches or relays actuated by a single coil. This relay has eight terminals, including the coil.
QPDT - Double Pole Throw Quad. Often referred to as Quad DPDT or 4PDT. These have four rows of terminals reformatting. Equivalent to four SPDT switches or relays actuated by a single coil, DPDT relay or two. In total, fourteen terminals, including the coil.
- Protection relay
- Real Overcurrent
- Distance Relay
Lightning, power surge INSULATION COORDINATION and
I. Introduction:
Systems Electrical inherently involves two forms of protection as current and voltage over current protection of electrical equipment are well known to all, are not produced here. Protection against overvoltages on the other hand, remains a relatively new to many engineers. The two types of protection as necessary for the security of the operating system.
The importance of protection against overvoltages on the power system not be overemphasized. major equipment failures, costly repairs, personal safety and plant downtime are consequences of lack of protection against surges.
The surge protectors are designed to limit the dangerous surges in the system. If lighting or the value system of safe production when they occur in Power Systems. A flash device is a voltage limiter. The functions are available for downloading from the energy associated with a system voltage conditions on the boundary and the interruption of the scholarship current that follows transient current through the barrier and return to a state of isolation prepared for the next case more power.
In fulfilling its voltage limiting function, protection against lightning of certain features must be coordinated with isolation levels in force in the protected system. Isolation is a key factor to consider in the application of lightning in a system. Coordination isolation is only a small part of all subjects of application surge. Several other factors must also be considered by the engineer the selection of protection against surges. The location of the stem, the interconnection of son of soil, the isolation level of protective equipment and qualification of surge arresters are important in the protection of equipment against the harmful effects on blood.
Lightning II.Surge operation:
The basic operation of an arrester is unique. As noffi1al, a lightning rod to act as an insulator. When a wave of high voltage is produced. The arrester must cease to be an insulator and must turn in a short circuit in millions Therefore, in one second. The operation of the type most widely used value surge, it is a kind of lightning rod. Other types of lightning, such as barrier removal and oxide Line cutting (Downloaders without breaks) are on the decline or too new for a general discussion at this time. The active elements of a Cutting-valve type are the sparks and block valves. they are in a tank in china for the protection of the atmosphere and the outer insulation.
The empty set is a series of air holes in the series with the dielectric strength sufficient to withstand the most frequency of the power system. For more severe stress conditions the gap is always lower than the breakdown voltage insulation withstand voltage level teams that are protecting other damage output wise and downtime or a plant. differences serves as a switch that turns on the rod. level of tension during which the stem is passive (insulation) to the active (conducting) state, is called spark more tension.
The valve block control what happens after lightning ignited. If a gap is used only once a surge has been diverted to the ground, a dead short between line and ground and power system 50 Hertz current attempts to land causing fuse, to become closer, or switch to operate the interruption of the failure of the current system.
Element Valve does exactly as its name indicates. Performed when the current flows and continue to increase if the line 50 Hz begins to flow. the valve block is able to do so because it is made of non-linear resistance material of silicon carbide. The control block provides a very high resistance 50 Hz time that shows a low resistance to surge. In addition, it also consumes more energy through it.
Spark and discharge voltage are two characteristics of protection against lightning, which are used to calculate margins of protection during the trial coordinating isolation. These protections are published by manufacturers of lightning.
III. Arrester Rating:
There are three classifications of arresters used for protection of power through a system.
1.Distribution Type:
The arresters are generally used in the distribution of security systems equipment. distribution arresters standards are used to protect the oil. isolation of distribution transformers, these arresters are also used as input line 11kV and 22kV lines. They are the lowest cost.
2.Intermediate Type:
These units cost about two or three times more than the distribution of equivalent units. To this end, the rod provides maximum spark voltage and discharge characteristics that give greater margin of protection capacity compliance levels of high power. These downloads also have a pressure system for evacuation internal pressure if the device falls before porcelain shell has the possibility of failure. They are used for protection against lightning of power transformers in the sub-transmission and LV ie110/33/22/11KV 66/22/11KV post office.
3.Station Type:
These arresters offer the best features of protection and greater heat capacity, but cost twice the equivalent of intermediate units. As arresters station through a pressure relief system to evacuate the internal pressure if the device fails before the deposition China has the possibility of failure. These arresters are generally used at 230 kV, 110 kV and 66kV.
4.Basic Insulation Level:
Basic Impulse Insulation Level (BIL) is the level of insulation voltage equipment can withstand without damage. The insulation withstand voltage is a function of time. In to establish levels of tension-time isolation pulse transformer impulse test standard withstand voltage tests are the norm in selected units as a type test. The pulse transformers are subjected to stress tests (BIL has rated) and a chopped wave test (15% above BIL). A steep front – Tests wave (65% above BIL) were also performed on some units. A curve traced by these three points defines the insulation minimum resistance to the curve for the isolation coordination (Fig. 3) The real resistance level for the transformer is above the curve drawn.
5. Arresters request:
With an understanding of how a lightning discharges its functions and knowledge insulation of equipment, we can now move to the area of application and consider the various factors that make up the application thrust towards the protection of the terminal voltage processors, the choice of surge protection are worth careful consideration. Several factors must be taken into account to arrive at a reliable solution and at the same time, the protection activities. The important points are:
i) selection rated voltage.
ii) The selection by the rules, codes, recommendations for insulation coordination.
i) Assessment SPD:
The nominal voltage of a lightning arrester is defined as the highest voltage of 50 Hz when the arrester is designed to operate, and close to his office after a wave has passed. Due to the implementation of the system grounding and the connection, the stress is often higher than the voltage phase to earth / in the phases of health and temporarily increase depends on the decision land or system. The choice of a nominal voltage of the cutting station depends on the connection of the land and the nominal voltage of the system.
In addition, the voltage across an arrester during a discharge is directly proportional to the nominal voltage surge that is, an increase of 10,000 Ampere product a discharge voltage higher if it runs through a 10KV downloader what is sunk by a lightning conductor is generally desirable 9KV in terms of protective equipment to select the lowest voltage rating for the application.
ii) the location Lightning:
Surge arresters must always be located as close as possible to the terminals of the protected equipment. To protect transformers, lightning transformer mounting directly into the best insurance. A substantial distance between the arrester and the protected equipment reduces the protection offered by the flames and also increasing the voltage applied to the processor when the discharge voltage. Also because of the extra distance between Travel equipment and lightning, the waves could increase beyond the point of the team damaged before the lightning came to her rescue.
No Furthermore, the lightning rod cables should be as short as possible, because of its contribution to the current discharge voltage. During the passage of current grounded by a conductor, the interconnecting cables to make a contribution of stress to the current success through impedance. Depending on the magnitude of the wave, the rate of increase of the driver, a typical value of the contribution of voltage to the discharge voltage by interconnecting cables 1.6 KV / ft.
In practice, the protection of the range is given by the simple formula.
L = U – Ua When V x
2 XS
L = range of protection against lightning meters
(Measured along the line)
U = Voltage keeping equipment protected KV. (BIL equipment)
Vout = Voltage spark a lightning rod kV (peak) system. Ground fault conditions, the voltage
V = speed of progression of the wave
Line V = 300 m / sec microphone.
V = 150 m cable / micro sec.
S = slope of the wavefront in the entrance KV / sec.
(Protecting a series of increases with the difference between lightning impulse voltage and voltage IV Go spark Therefore, a downloader with the level of protection tends to broaden the range of protection)
iii) interconnection Field:
It is essential that the arrester ground terminal will interconnect the transformer tank and secondary neutral to ensure a reliable protection cons Surge processors.
Iv) coordination insulation.
Now, we consider the choice a lightning conductor according to the rules, codes or recommendations regarding the coordination isolates. The calculation of the margin of protection is the main part of a file. insulation coordination of the study. Insulation coordination is the process of comparing the power of isolation stress that may be a lightning rod for the severity of the discharge voltage for which protection is sought. For a transformer, this means comparing the voltage insulation withstand time curve of momentum and come back and cause a new wave discharge curve of voltage arrester.
After determining the rated voltage of a lightning rod, the level of protection must be carefully selected. For complete protection equipment, the level of "protection" to know. the level at which the stress on the arresters are omitted, must be below the level of support by a factor of at least 1.2 for lighting surges and cons 15 for switching overvoltages. The value thus selected should be compared those on the ISS or the technical details provided by the manufacture of lightning.
To achieve the discharge voltage of a system discharge of these calculations for a discharge voltage 10,000 amps. increase is used normally. The following formulas define these two margins of protection calculations:
FOW-IX CWW SO + BIL-DV)
MP1 MP2 to CWW = x 100% = 100% x BIL
Where
In greeted CWW = Picado-withstand voltage transformer winding BIL = 1.15
NA = FOW Wavefront further spark KV (CREST)
BIL = Basic insulation level Impulse transformer.
DV = discharge voltage 10 kA place.
input voltage IX = connecting cables at a rate of 1.6 KV / m
MP = Margin of Protection
Insulation coordination, appearance important consideration in protection against surges must be granted to processors with reduced BILS
vi protection against Direct impacts:
i) protection against direct hits can be handled by the shield of the team for the delivery station any
a) the mast or son or
b) a network cable above ground so that the equipment and the switches are all in the protected area.
ii) The protected area of the bar of a mast is generally accepted as a cone with base radius equal to the height of the rod or pole on the ground.
iii) For smaller stations may be sufficient to run a cable from the front IM station from the towers of the adjacent line. additional cables can be run from the tower structure and the station.
iv) The grounds Shield station must be securely attached to the bus station to the ground to avoid the potential difference between the increase in armor and other g parts of the station text.
SECURITY IN SUB-STATION
Preventing damage to equipment and men who work in is then due to accidents an essential aspect of all creation. The prevention of accidents, which is a more important aspect is unexpected any business or organization.
Accidents occur mainly due to the implementation behaviors and circumstances, these accidents can be prevented by taking safety measures, the implementation of safety procedures and comply with safety standards.
general methods of security:
I. Although the implementation of all labor, some equipment or online must be isolated from the source.
2. Using bars of unloading, loading, whether it is the current download.
3. Using the Earth bar, all steps / conductive path is taken from the land belonging to ensure proper grounding.
4. Even opening a switch or withdrawal of AB fuses, it is also advisable to use rubber gloves and preferable.
5. Wearing a belt of rope is another method of security taken for working at heights.
methods Security Council adopted in the posts:
In any work to be present throughout the line first and foremost, the subject of work is to obtain the authorization of the competent authority to oversee the implementation of the work, including the date, time, duration, work, parties, etc. affected.
Grid for departures and positions, the official responsible for issuing Authorities are SE (LD Centre), Madras, for 110 KV, 66 KV lines radial Superintending Engineer / Distribution is the competent authority. Similarly, the InCharge 33 KV Distribution Engineering Division is the competent authority.
Information above with the list of authorized agents attached (Annex I)
Without the authorization of the competent authority may be issued or SC approved person. If the above procedure is not followed, nor a suicide. In addition, it is also the killing of others.
Thus, after receiving proper authorization from the clear position must be issued, the requested Party. But the subject and the recipient must be aware of / have full knowledge Details SS team, the panel control room etc.
The person must clear line emission clearly understand the following:
a) What triggered the switch
b) What are the changes open AB
c) If the soil is
d) What is the safest place / Line to complete the execution of works
Security Devices Control Room:
A) Key board should be able to open so that keys can be removed quickly in an emergency.
Keyboard clear line must be closed until can prevent others using the keys inside, before the cancellation of the permit of the clear line.
Keys should be placed on the tray key in an orderly manner according to their number. Otherwise, the requested lock could not be opened in time and opportunity to open a lock wrong can happen.
2) rubber mat should be provided on the ground in front of the board.
3) following information must be clearly visible in the control room.
Approved operating instructions for all equipment.
Breaking the instructions.
Instructions even for emergency operations to perform when running the Buchholz relay. differential relay, Travel in the control group, a total blackout network failure. The operator must be thoroughly familiar with the instructions above and must be able to act quickly and effectively.
4) The DC Commission that contains the provision of cable. A design of panel wiring diagram design and grounding must be displayed in the control room. It is necessary to attend the faults immediately after his accident.
5) GFCI DC system should be available.
6) It should not be defective sockets, switches and taken in wiring the control room.
7) A respirator should be available in the Ready state.
stools made of insulating material be used for the operation of high voltage equipment of communication (telephones).
9) appropriate number of rubber gloves, rope belt and discharge bars rods of land in good condition should be available at the control room.
Battery Room
1. battery room must be enclosed in the condition.
"Open flame is prohibited in the hall of the battery "and" no smoking "written warnings must be kept in front of the battery compartment.
2. A fan should be running.
3. Accurate test cell volt DC meters, thermometers and water meters must be available in the battery room.
4. pilot cell voltage, specific gravity and the temperature must be taken each week.
5. The specific gravity should not be kept below in 1195 to 15.6 º C and below the 1183-32 years. 20 ° C. The battery should never be allowed discharge below 1160.
6. Cell voltage should be between 1.95 V to 2.05 V. The battery should not be allowed to discharge below 1.85 V.
7. Batteries should be allowed or not to charge more tax insufficient. It should also be slowed.
8. electrolyte level should be checked every shift. You must ensure that the level is 10 mm above the top plates.
9. small cells must be corrected in time.
10. While taking density readings, careful not to allow the acid contact with eyes.
Security measures for processors:
1. Transformers will be updated regularly, on schedule. High-voltage switches on each side of the low voltage must be isolated after the reduction of the load, activation of the breeze.
2. Kiosks and OCB: All live parts of the tape from the cockpit must have exc. To be protected under the gauze. It must be protected against rodents. The keys are kept with the latch. When once to open the door of the kiosk, kiosk stumbled link should be opened by the key lock. The opening of links must be physically verified. After having taken all precautions before, the tank must be reduced. adequate care must be taken and must be taken into account that the offer is on the roof.
oil leaks must be stopped. Back feeding is avoided.
Cotton waste should not be used for cleaning.
3. Switches AB:
Managing the switch B must be grounded. The leaves should be kept in the open position. It should not be automatically closed, maintenance must be done for her. AB Reed will be completely open. AB switches remains fixed in the two conditions. AB switches opens Only after tripping circuit breakers.
. Lightning 4:
arresters are used to circumvent Suddenly the beam and thus protect the computer. Only after the download completed correctly on the rod, you should try to answer maintenance.Fencing be provided around the lightning. Conventions door lock must be provided. Separate links are provided for land lightning.
5. Current Transformers:
Transformer secondary current is a short-circuit during maintenance and testing. Before any test, the current transformers must be met.
6. Voltage transformers:
potential side of the transformer primary should be grounded for maintenance and testing. The secondary side is set to be connected grounded in one place. Each time a connection or delete feet in the secondary side of the potential transformer fuses to die must be removed and renewed.
7. Coupling capacitors and capacitor HT:
Capacitors must be provided in the fence. Before attempting any work good performance should be done. Should be attempted for maintenance. Grounding must be provided during construction. After completion, the soil must be removed.
8. wells of the Earth:
ground connections sub-station shall be properly maintained so that the ground resistance is minimal. Water should be poured over the boxes of earth daily. grounding must be able to protect people who work in electrical and protection during a high current fault. resistance to ground shall not exceed the following limits.
Grid Stations: I Ohm other substations .. 2 Ohm.
Distribution transformers .. 5 ohms.
Should be a clearance of 5 feet between the fence and the substation equipment items Electric. The fence shall be grounded every 200 meters separately. In general, the soil should not be closely related to Last land sub-station. But when the height is less than 5 meters above the ground near the feet must be tied to the grounding of the post. Doors Closing iron in the sub-station should be grounded separately.
9. The Fire Equipment:
These teams are to be in good condition and working. proper maintenance schedule should be done to keep them in good condition. These teams should be kept in an easily access to the emergency use immediately below. very dry sand, applied whenever necessary. empty buckets should be provided.
10. SS Yard:
1. SS fences would patio.
2. Unauthorized persons must not enter the court
3. ducks cable will be supplied with the flagstones.
4. Better lighting is required for the court.
Five. A display of a warning that "Umbrella" Dogs should not be sued in the court "must be given in the courtyard.
6. A separate room is to provide for the maintenance of empty drums. Upon entering the room "No Smoking" board of directors must be provided.
General
1. The territory of the operating point which has been declared to security must be clearly identified by attaching a rope. In This limit is set by hanging a green flag. Outside this limit is not safe to work must be identified by a red flag.
NOTE 2. If necessary, and "Men at Work" Do not "is safe for work", etc., must be provided.
3. If an unauthorized, unqualified personnel moving near the equipment, it can done with the assistance and under the supervision of a trained and authorized personnel.
4. The conversation is strictly forbids execution any work of cunning. It should be totally avoided, especially when the work is carried out at any bar.
5. Establishment of materials, tools and plants and people must be at a safe distance from the Live. parties.
6. T & P, such as keys, etc. must be lifted and lowered by ropes only and not throwing and catching.
7. Study and a ladder safely with measurements at intervals be appropriate to use. To avoid sliding scale, to take necessary precautions in the bottom of the scale, providing Gunni empty.
8. Elevation of stairs or bars (the Earth) will take place only horizontally. Vertical
Lifting may cause damage break with the safety distances.
9 links art bus line, which remains open to work on the OCB and
About the Author
I have a 3400 Chevy Venture-motor-Can you tell me what I want to see if I have blown a gasket? or head cracked?
A model 97 with 180k miles. Water heater does not heat. Water Pump replaced (3x), the last on a 35k miles ago. Do not miss, no water seems to be oil, not by the tube steam leak or hole in the muffler (ha). Just replace the thermostat, two days ago. Now, after replacing the gauge temperature thermostat will all road and then back down to cold. Constantly! Mechanic was Drinking Stop leak several times in recent years, could this end the base heater? or blown head gasket or cracked head as he suggested. After heat has been replaced again the day and bled the lines of three or four times and the heating is never so hot HEATING tibia. When recrank, no heat again. Even if the temperature gauge goes all the way up, without heat. He said he may have to leave the vents open at night and remove all air. Any suggestions or recommendations. I am mechanical Chalenger. By Please be nice!
First, your car has an automatic control system temperature (This is a system that automatically maintains the preset temperature of the carrier, also known as automatic control temperature)?. If so, it is complicated to achieve. Therefore, I can give an idea of what to look for. 1) Poor sensor ambient air, 2) Problem is mixed with. If you do not have this system, and you have a standard, full manual heating, then your problem is that the heating control valve is opened. Hope that helps and I recommend a new mechanic. With superior quality indicator may be Thaat bad tempature sending unit or the cable is loose.
HOW TO MAKE A FILTER
